Water Quality, Flooding, and CodeNEXT

If you’re a consistent reader of AEN or a follower of local news, you’ve been reading a lot about CodeNEXT lately.

(And if you haven’t, that’s okay too. As a reminder, CodeNEXT is the city’s effort to rewrite its land development code, which is basically a rule book for the city, explaining what can be built where. CodeNEXT will determine how Austin looks 10, 15, and even 50 years from now. And it will affect everything from affordability, to transportation, to the environment. In other words, it’s a really big deal.)

The bulk of the CodeNEXT conversation has tended to focus around housing, density, transportation, and gentrification. But there is another key component – water quality.

Why? Because as Austin continues to grow, more buildings are built everyday and more concrete gets poured. These non-natural surfaces are known as impervious cover because they don’t allow rainwater to filter through them. Instead, the water flows along the streets (picking up pollutants along the way) until it hits a storm drain or body of water. This can lower our city’s water quality and in times of extreme rain, lead to flooding.

That is, unless something is done to stop it. The city currently has several ordinances and policies in place to try and offset the effects of development on water quality and flooding. Now that CodeNEXT has the opportunity to revisit these policies, water quality and flooding are again hot topics of conversation.

Earlier this week, three local environmental organizations (Environment Texas, Clean Water Action, Save Barton Creek Association) shared their insight on the topic, publishing an open letter to city leadership all about water quality, flooding, and CodeNEXT.

Here’s what they had to say.

First, they explained what they like about CodeNEXT so far. In particular, they praised the new code’s increase in the use of green stormwater infrastructure (GSI), which uses natural features to capture and cleanse stormwater right where it falls. Examples include green roofs, rain gardens, and rain barrels.

They also praised a new change in the code which will require property that is being redeveloped to also make drainage improvements. Under the current code, only new developments must meet this requirement (or redevelopments that are increasing the amount of impervious cover when compared to the old development). This essentially acts as a loophole, grandfathering in old properties that were developed before drainage and flooding rules were passed. Under CodeNEXT, both new developments and redevelopments will be required to maintain runoff peak flow rates at pre-development levels.

Despite these improvements, the environmental organizations did note that when it comes to water quality, CodeNEXT is not yet perfect. In the next draft, they recommended that the threshold for water quality requirements (which are currently triggered when a development has 8,000 square feet or more of impervious cover) should be lowered to 5,000 square feet. They also recommended that the code change requiring runoff peak flow rates be maintained at pre-development levels should also be applied to new residential developments with 3-9 units (aka – missing middle housing).

“The second draft of CodeNEXT came a step closer to realizing Imagine Austin’s vision of a green city,” said the Save Barton Creek Association’s Executive Director Angela Richter, in a press release. “However, citizens must have a guarantee that they are not being placed in danger of increased flooding and decreased water quality as other Imagine Austin priorities are being met.”